The walkout threatens to leave without transport thousands of fans who will attend Thursday’s inaugural match of the 2014 soccer World Cup at Sao Paulo’s Arena Corinthians stadium.

The news about strikers being fired came soon after police used tear gas to scatter a group of demonstrators who tried to block access to a metro station.

The state government said it can and will get tough with strikers under the Regional Labor Court ruling that declared the strike illegal.

“Who got fired? Those who had already been booked for vandalism, improper use of the subway, who physically blocked access or who incited the public to enter without paying. In conclusion, those who committed the most serious offenses,” the transport secretary of Sao Paulo,Jurandir Fernandes, said on a local radio station.

Only 255 of the 1,534 metro employees scheduled to work Monday morning actually showed up.

Fernandes said the metro is technically capable of taking back workers who have been dismissed, and also has the power to hire contractors on an emergency basis.

Metro workers decided at a meeting Sunday that they would stick to the walkout despite the court ruling.

Sao Paulo Gov. Geraldo Alckmin ordered police reinforcements sent to all metro stations to guarantee security for employees wanting to return to work

Despite the strike, two of the five metro lines were operating normally on Monday, while trains on the other three were operating but not all their stations were open.

The Regional Labor Court also said the union must pay a fine of 500,000 reais ($222,000) a day if the shutdown continues.

The court at a conciliatory hearing set a wage hike of 8.7 percent for workers on the state-government-run Sao Paulo subway, compared with the 12.2 percent demanded by the union.

“We have a World Cup, the biggest sports event in the world. The state government has elections late this year (October), it has to negotiate. We have to confront the government,” the union president said in justifying the decision to continue the strike.

Public sector unions in the 12 Brazilian cities hosting World Cup matches have been taking advantage of the approach of the June 12-July 13 competition to press demands for higher pay.

At the same time, social groups are staging protests over the huge sums of public money spent on the competition.